The first capsule was developed in the mid-1990’s and was given FDA approval for use in the U.S. in 2001. It was approved as a first line small bowel imaging modality in 2003. Since that time, there have been over 500,000 ingestions of the capsule and nearly 1,000 scientific articles about its clinical use.
What are the components of WCE?
The system consists of a sensor array, or electrodes, which are attached to the patient’s abdomen, much like EKG leads or a Sensor Belt, worn around the abdominal area. These are connected to a data recorder which is worn by the patient during the study. The capsule, which is swallowed by the patient, is 26mm x 11mm in size, and consists of an optical dome, a lens, several light emitting diodes, a semiconductor, transmitter, and an antenna. The disposable capsule is propelled physiologically through the entire GI tract, taking its most accurate images in the small bowel. Images recorded by the capsule camera are transmitted and stored on a data recorder worn by the patient. After the study, the images are downloaded onto a computer where the images are then viewed and interpreted by a specially trained gastroenterologist. Dr. Simoni was a pioneer in use of capsule endoscopy and implemented it in his fellowship program as well as mentoring other physicians interested in WCE. Dr. Simoni has performed numerous successful of WCEs since 2003, just 2 years after FDA approved the procedure in the United States.
How is the procedure performed?
A minimal bowel prep to clean the intestine may be recommended to take the night before undergoing a capsule endoscopy. The exam is usually done in an office setting. Sensors are placed on the patient’s abdomen and the data recorder is attached to a large belt worn by the patient. The capsule is then activated and swallowed with a sip of water. The patient may leave the doctor’s office and continue with routine daily activities, including eating a light meal after several hours. Later, the patient returns for removal of the equipment, and then returns home. There is no sedation needed for the procedure and it is completely painless. The capsule is disposable and usually passes out of the GI tract unnoticed. The results are discussed in a follow up appointment with the patient’s doctor.
What are the indications for WCE?
The most frequent indication for performing a capsule endoscopy is the evaluation of obscure GI bleeding. Patients who have unexplained iron deficiency anemia or are losing blood from an unknown source in the GI tract are first evaluated with a colonoscopy and upper endoscopy (EGD). However, if these exams show no identifiable source of blood loss, then a capsule endoscopy study is the next step in trying to find the cause of the bleeding. About five percent of all obscure GI bleeding emanates from the small bowel, most often from small vascular lesions called angioectasias. These are small blood vessels with thin walls that may be found throughout the GI tract, and may bleed profusely or very subtlely over an extended time. Other causes of bleeding from the small bowel include ulcerations, erosions, inflammation, tumors, masses, or rare hereditary conditions.
Another common indication for capsule endoscopy is evaluation for Crohn’s Disease. Crohn’s is an inflammatory bowel disease which can affect the small intestine causing pain, inflammation, ulceration, and bleeding.
Small bowel capsule endoscopy is also a useful tool in evaluation of the small bowel for tumors such as lymphoma, carcinomas or carcinoids. This technology can be beneficial as an adjunctive diagnostic study in patients with celiac disease and for surveillance in patients with hereditary polyposis syndromes. Other potential indications for capsule endoscopy are under consideration and may include the evaluation of certain types of abdominal pain, refractory diarrhea or malabsorption.
Are there any contraindications to WCE?
Yes, known small bowel obstruction is a contraindication for capsule endoscopy. Patients who are at risk for obstruction have swallowing disorders, have pacemakers or other implanted cardiac devices, or are pregnant should have careful evaluation by a specialist before undergoing a capsule endoscopy.
Are there any limitations for WCE?
Yes there are limitations. WCE or capsule endoscopy system is purely diagnostic and is not used to biopsy or treat any conditions. Therefore, if any significant abnormality is found, further evaluation may be necessary.
Are there any risks of having WCE?
The primary risk with capsule endoscopy is possible retention of the device in the small bowel. In patients who undergo the test to evaluate for bleeding, the risk is very low, approximately one to two percent. For patients with Crohn’s Disease, the risk may increase to four to five percent. Most cases of retention resolve spontaneously after a short delay in the passage of the capsule, and most patients have no symptoms whatsoever. Occasionally, medications are given to help facilitate passage. In rare instances, there is an abnormality in the small bowel which blocks the passage. In such a case, the capsule can be retrieved during an endoscopic procedure called a double balloon enteroscopy, or in unusual instances, by surgical resection. Capsule retention generally indicates an abnormality in the small bowel that would need further attention.
If Dr. Simoni is concerned about a possible blockage in the small bowel, a patency (or ‘dummy’) capsule can be ingested as a test beforehand to insure that no blockages exist.
Here is a short video about Wireless Capsule Endoscopy (WCE):